[Greenbuilding] Build tight, ventilate right

[John Straube]

Natural ventilation is ventilation driven by natural forces. Mechanical ventilation is ventilation driven by mechanical equipment. 
Natural ventilation can occur through ducts, or grilles, or any intentional openings. It can be driven by wind, or buoyancy differences induced by temperature differences.

Air leaks are not really ventilation, as they are by definition accidental openings driven by unknown forces. Describing this as ventilation is like saying that having your car roll over in the ditch after the tire blew is parking the car. The car is left in a certain spot (air does enter/leave the building) but you have no control over when this occurs or how much.


Nick Pine wrote:

> John Straube <jfstraub at civmail.uwaterloo.ca>
> 
>> Once you have an airtight house and quality (read efficient) 
>> ventilation system, natural ventilation does not really save a 
>> worthwhile amount of energy in houses but causes all kinds of 
>> challenges for construction design and operation while remaining 
>> unreliable.
>> In large buildings, natural ventilation may be worth the effort, but 
>> in a typical SFH, hardly.
> 
> "Natural ventilation" as in air leaks vs exhaust fans?
> 
> Nick 
> 
> 
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-- 
Dr John Straube, P.Eng.
Associate Professor
Dept of Civil Engineering & School of Architecture
University of Waterloo
Waterloo, ON Canada